Press for ferrite cores



' Jan. 27,1970 R. M. GUSTAFSON 3,491,407

PRESS FOR FERRITE CORES Filed Dec. 18, 1967 5 Sheets-Sheet 1 FEGJ 70 k F74 INVENTOR ROBERT M. GUSTAFSON WWW ATTORNEY Jan. 27, 1910 R. MlGUSTAFSON 3,491,407

PRESS FOR FERRITE CORES Filed Dec. 18, 1967 5 Sheets-$heet 2 FIG.2

I 141 92 4e 139 as. \80 e4 406 46 m l I Jan. 27, 1970 R. M. GUSTAFSONPRESS FOR FERRITE CORES 5 Sheets-Sheet 5 Filed Dec. 18, 19s? Jan. 27,1970 R.. M. GUSTAFSON, 3,491,407

PRESS FOR FERRITE corms Filed Dec. 18, 1967 s Sheets-Sheet 5 UnitedStates Patent U.S. Cl. 1816.5 7 Claims ABSTRACT OF THE DISCLOSURE Thisinvention provides an improved support for the upper and lower punchesof a press for making toroidal cores from powdered ferrite material.Each punch is mounted on a pair of flexible beams. The beams areconstructed to flex slightly in the direction of intended motion of thepunch but to be rigid in every other direction. This flexing providesthe only motion of the upper and lower punches. The new supportstructure provides improved alignment of the upper and lower punches andthe stationary die cavity and thereby reduces tool wear and permitspressing smaller cores.

THE PRIOR ART Ferrite cores are small toroidal elements that are used inmagnetic storage devices for data processing apparatus. Cores usuallyhave an outside diameter of about a few tens of thousandths of an inch.Smaller cores can be driven harder and thereby switched faster thanlarger cores, and improvements in the speed of ferrite core memorieshave been closely related to advances in manufacturing smaller cores.

A core press usually includes a stationary element that has acylindrical aperture that forms the outer cylindrical walls of a diecavity, a second stationary cylindrical element that is located coaxialwith the die cavity and forms the inner walls of the die and theaperture of the pressed core, a movable lower punch that is coaxial withthe inner stationary cylindrical element, and a movable upper punch. Theupper punch is movable to press the ferrite powder into shape, and thelower punch is movable to raise the pressed core out of the die after ithas been pressed.

In the prior art, core presses have been developed from pressesoriginally designed for pressing pills. The pills are of course muchlarger than ferrite cores, and the tolerances between the moving punchesand the supports for a pill making press are of course much wider thanthe tolerances for a core making press. In these prior art core presses,the punches are mounted on cylindrical supports that reciprocate axiallywithin cylindrical openings in a support. These elements are made veryaccurately to produce a close sliding fit between the movable parts andtheir supports. Nevertheless, the alignment of these presses has beendifficult and as a result, tool wear has been a recognized problem.Furthermore it is doubtful that core presses of this type can be furtheradapted to permit pressing cores that are much smaller than the coresnow being pressed. One of the objects of this invention is to provide anew and improved core press (or similar device) in which thereciprocating parts maintain very accurate alignment.

In these prior art core presses, the punches have been operated througha fixed distance and the cores being made on a press at about the sametime all have the same height. When cores are pressed in this way to afixed height, the density of the cores tends to vary and magneticcharacteristics that depend on density can be degraded. Core pressoperators routinely test weight the cores and adjust the press to varythe core height as is appropriate to maintain the desired core density.

3,491,407 Patented Jan. 27, 1970 The prior art has suggested corepresses which operate to give the cores a uniform density rather than afixed height. However, these presses have used hydraulic drives whichhave been undesirably complex. A more specific object of this inventionis to provide a new and improved core press that presses cores to apreset density rather than to a preset height.

THE INVENTION The core press of this invention uses dies and punchesthat are generally similar to the prior art core presses alreadydescribed. According to this invention, the upper and lower punches areeach carried by a pair of flexible beams. The beams have their outerends fixed to the stationary supporting parts of the press. A punch ismounted between the pair of beams at the midpoint between the fixedends. The beams are constructed to be sufliciently flexible to bemovable vertically a few thousandths of an inch. In other directions thebeams are constructed to be essentially rigid. Suitable means isprovided for reciprocating the upper and lower punches to operate thepress through a core pressing cycle.

In the preferred press, the upper punch is driven by a direct mechanicallinkage and thereby is operated over a fixed path. The lower punch isoperated directly by the drive mechanism only during the operation ofejecting a core from the die cavity. During the pressing operation, thelower punch is supported by the lower pair of flexible beams and,preferably, by auxiliary spring means. The

beams and the springs are constructed to provide essentially constantforce on the core material in the die cavity over the range in variationof core height that might be experienced. Thus, this press producescores having preset density and slight variations in height.

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of a preferred embodiment of the invention, as illustratedin the accompanying drawings.

The drawing:

FIG. 1 is a front elevation of the preferred press.

FIG. 2 is a section 22 of FIG. 1.

FIG. 3 is a section 3-3 of FIG. 1.

FIG. 4 is an enlarged section of the punches and die as shown in FIG. 2.

FIG. 5 is a perspective with parts removed.

THE PREFERRED PRESS Introduction The simplified perspective of FIG. 5 isa helpful introduction to the more detailed showings of the otherfigures. The'press includes a base 12 that supports the other elements,and a support 16 that supports the die and the punch carrying elements.A front support 13 and a back support 14 are arranged to positionsupport 16 at about the vertical midpoint of the press structure. Aswill be explained later, cores are punched within a die held by support16, and the pressed cores are ejected onto the upper surface of support16. An upper punch and its associated components are mounted above thesupport 16 and a lower punch and its associated components are mountedbelow support 16.

A pair of elements 18 and 19 are mounted on support 16 to position aflexible beam 20 slightly above support 16. Beam 20 is somewhat H-shapedto be as wide as elements 18 and 19 at its ends and to be somewhatnarrower between its ends. Elements 21 and 22 cooperate with elements 23and 24 to position a second flexible beam 25 above and parallel to beam20. A rigid spacer 26 is mounted between beams 20 and 25 at the midpointbetween their ends to support the movable elements of 3 the upper punch.A plate 27 is mounted over beam 25 and spacer 26.

Similarly, elements 30 and 31 support a flexible beam 32 closely belowsupport 16; elements 34, 35, 36 (hidden in FIG. and 37 support aflexible beam 39, and a spacer 40 is mounted between the beams. Theinner beams 20 and 32 carry the punches, and the outer beams 27 and 39function primarily to laterally stabilize the outer parts of the punch.

FIG. 5 also shows that wall 13 has a cut out portion that forms asurface 41 that supports stationary parts of the lower punch assemblythat will be described later. A surface 42 is numbered to show therelationship of FIG. 5 to FIG. 2. Wall 14 has a similar cut out portionand surfaces 43 and 44 not shown in FIG. 5. FIG. 5 also shows a smallopening 46 formed in wall 13 which receives an element (106) of thelower punch assembly which will be explained later in the description ofFIG. 2.

Mechanical drive FIGS. 1 and 3 show the mechanical drive and itssupporting structure. Side elements 50 and 51 and a top element 52 aremounted on the base 12 to form an open, box-like, structure thatsurrounds the components already introduced in the description of FIG.5. A gear 53 is mounted on a shaft 54 to be supported and driven from asuitable source that is not shown. A gear 55, shown also in FIG. 2, ismounted on a cam shaft 56 and is arranged to be driven from gear 53. Camshaft 56 is rotatably mounted below base 12 by means of bearings 57 and58. Cam shaft 56 carries a cam 60 which drives the lower punch.

A gear 63 is mounted on a cam shaft 64 and is arranged to be driven fromgear 53. Cam shaft 64 is rotatably mounted in bearings 65 mounted onside elements 50 and 51. (Bearings 65 are shown only in FIG. 3 and areto be distinguished from the space 66 shown in FIG. 2.) Cam shaft 64carries a cam 68 that operates a powder feed mechanism that is shownonly in FIG. 2 and will be described later.

A gear 69 is mounted on a cam shaft 70 and is coupled through a gear 71to be driven by gear 63. Gear 71 is mounted on a shaft 72 that ismounted on the side element 50. Shaft 70 is rotatably mounted onbearings 73 and 74 which are mounted on top element 52. Shaft 70 carriesa first cam formed of elements 75 and 76 and a second cam 77. These camsraise and lower the upper punch.

The die and the lower punch FIG. 5 shows the general relationship of thedie and the lower punch to other components that have been describedalready. The die (89 described later) is mounted in the support 16. Asupport 80 is mounted below support 16 to hold a stationary die rod (93described later). Support 80 is shaped to be spaced away from support 16in the region of the die to provide space for the upper portion of thespacer 40, which carries the lower punch (90, described later). Thespacer 40 is driven from the lower cam 60 (not shown in FIG. 5) througha rod 82. Rod 82 engages a flexible element 83 that extends throughopenings in the sides of spacer 40 and bears against elements 84 formedon the sides of spacer 40. Rod 82 is removable from element 83 tofacilitate assembling these elements.

FIG. 5 also shows a stationary stop element 86 that is mounted onsurface 41 of front support 13 and a similar surface of back support 14.A guide 87 is mounted on stop 86 to guide the rod 82. Stop element 86extends through the spacer 40 to bear against a movable stop (95,described later) carried by spacer 40. When the lower punch (90,described later) is driven to its uppermost position by cam 60 and rod82, the lower punch assembly stops against stop element 86. Furthermotion of the 4 rod 82 then slightly flexes the flexible member 83 butdoes not further raise the lower punch.

FIG. 4 shows the details of the die 89 and the lower punch 90. Support16 is provided with an aperture for receiving the die. The die isprovided with a flange that fits against the lower surface of support16, and screws that are not shown fasten the die to the support. Die 89has a cylindrical aperture 91 that has a diameter of about .006". Thisaperture forms the outer walls of the die cavity and shapes the outercircumferential walls of a core.

The lower punch 90 is shaped to extend into the aperture 91 and to formthe lower wall of the die cavity. Lower punch 90 is also shaped to bemounted on the lower surface of the upper portion of spacer 40 by meansof screws, not shown. The lower punch has an axial bore for receiving astationary core rod 93. Core rod 93 forms the inner walls of the diecavity and shapes the aperture of a core. Core rod 93 is tightlythreaded in an element 94 which is mounted on support 80, and the corerod is adjustable to set up the press.

FIG. 2 shows in a reduced side view the elements that have beenintroduced in the description of the front view of FIG. 4. FIG. 2 alsoshows the movable stop element 95 which was introduced but not shown inthe description on FIG. 5. Stop element 95 is fixed to the lower portionof the spacer 40 and the lower flexible beam 39. When the lower punch isin its uppermost position, element 95 stops against the stationary stop86.

In FIG. 2, unshaded portion of the stationary stop element 86corresponds to the vertical surface of the slot that FIG. 5 shows formedin the lower surface of stationary stop 86, The slot is constructed toreceive a thickness gauge for adjusting the clearance between elements86 and 95 when the lower punch is in its lower position.

The movable stop 95 is also constructed to bear against a preloadedspring assembly 96 when the lower punch is in its lowermost position.The preloaded spring assembly includes a spring 98, housing elements 102and 103, and an element 104 that slides within the housing to transmitthe force of spring 98 to the stop 95. Stop 95 is adjusted to engage thespring assembly near the lowermost point of the travel of the lowerpunch and to thereby provide a predetermined spring force opposing theforce of the upper punch. The spring assembly 96 is easily replacable asa unit to change the force that the press applies to a core.

As the press has been described so far, the cam 60 drives the lowerpunch upward to eject a core at the end of a pressing operation and theflexible beams 32 and 39 lower the punch for the forthcoming operationof filling the die cavity with powder. A circumferential groove isformed on the movable stop 95, and an element 106 is shaped at one endto engage the groove of element 95 and at its other end is mounted on arod 107 that is pivotably mounted between supports 108 and 109. (SeeFIGS. 1 and 2.) A lower element 112 is mounted at one end on a rod 113that is pivotally mounted on a support 114 that is mounted on the lowersurface of base 12. Element 112 is adapted to ride on the lower surfaceof cam 60, and a rod 117 connects elements 106 and 112 to transmit thedownward force of cam 60 to the lower punch. Rod 117 is made adjustableto establish the desired relationship between the position of the camand the position of the lower punch.

The upper punch The simplified drawing of FIG, 5 shows an upper portionof the upper punch 118, an element 119 that is mounted above the die,and a rod 120 that is arranged to engage punch 118 and to extend abovethe upper portion of the spacer 26 to ride on the upper cam element 77(not shown in FIG. 5). A screw 121 shown in FIG. 5 cooperates with otherelements to raise the upper punch at the end of a core pressingoperation. The upper punch has a slot 122 that cooperates with anopening 123 formed in spacer 26 to receive the powder shute.

FIG. 4 shows the upper punch 118 as it is mounted with element 119 onthe lower portion of spacer 26. The upper punch is provided with anaxial bore (not shown) that communicates with an air supply fittingmounted on element 119. After the punch has been raised, air pressure isapplied to clear the punch of loose powder. The air tends to bedeflected from the powder shute and to help move the core to the rightin FIG. 4.

As FIGS. 1 and 2 show, the rod 120 rides against the cam 77 that iscarried by the cam shaft 70, Cam 77 operates the rod and the upper punchthrough a fixed downward path for pressing a core. Cams 75 and 76operate through a rocker mechanism to lift the punch to its upperposition. The rocker mechanism includes an arm 125 that is pivotallymounted on shaft 126 that is held by a support 127 mounted on topelement 52. Rocker arm 125 carries a roller 130 that rides on the earns75 and 76. The screw 121, introduced in the description of FIG. 5, has alower rounded portion that engages a complementary shaped element 131mounted at the lower end of arm 125.

The powder feed mechanism FIG. 2 shows the general features of the powerfeed mechanism. Powder is held in a reservoir 136. A powder shute 137 isattached to the reservoir to deliver powder to the die cavity. Thepowder shute is arranged to ex tend through the opening 123 in spacer 26and to ride flush on the surface of support 16. The reservoir and powdershute assembly is mounted on a plate 138 that is pivotally mounted bymeans of a shaft 139 on a support 140 that is slidably mounted on thesupports 108 (FIG. 1 only) and 109 that were introduced in thedescription of the lower punch. The shaft 139 carries a roller 141 thatrides on the cam 68. For a pressing operation, the cam 68 drives thepowder feed components to the frontmost position illustrated by FIG. 2.After the lower punch has been raised to eject a core, the powder feedmechanism is pulled rearward by a spring 143 to a point where the powdershute covers the die cavity and powder fills the die cavity. A space 66is provided to separate the shaft 64 from the supports 108 and 109 andfrom the slidable support 140.

OPERATION To fill the die cavity, the upper punch is raised to itsuppermost position and the lower punch is kept in its upper positionfrom a previous core ejecting operation. The powder feed mechanism isthen driven rearward to cover the die and air pressure is appliedmomentarily to the reservoir to fill the die cavity with powder as thelower punch is lowered. As the powder feed mechanism moves over the diecavity, it pushes to the rear the core that was formed in the precedingoperation. Air pressure is applied to the upper punch to clear the pressof loose powder, and the air is deflected to the rear and helps to movethe core away from the area of the die. The powder shute is movedfrontward, and the upper punch is lowered to compress the powder to forma core. As the upper punch compresses the powder, it increases the forceon the lower punch and on the spring assembly 96. The lower punch movesa rather small distance under a substantially uniform force establishedby assembly 96. (A strain gauge may be mounted on the lower flexiblebeam 39 for monitoring the position of the lower punch.) Thus thedensity of the cores is quite uniform and they may vary slightly inheight. The upper punch is then raised by the operation of the rockerassembly, and the lower punch is raised to lift the pressed core out ofthe die cavity and into position to be moved rearward when the powdershute moves into the filling position. The lower punch is then loweredby the cam 60 and the flexible beams 32 and 39 or the elements thatcouple the cam to the adjustable stop 95.

While the invention has been particularly shown and described withreference to preferred embodiments thereof, it will be understood bythose skilled in the art that the foregoing and other changes in formand details may be made therein without departing from the spirit andscope of the invention.

What is claimed is:

1 A device for pressing a subject under a punch, comprising,

(a) a base,

(b) means mounted on said base to support said subject to be pressed,

(0) a beam constructed to flex slightly in One direction and to be rigidin other directions,

((1) means fixed to the beam only at the ends of the beam for mountingsaid beam on said base for said beam to be flexed toward and away fromsaid support means and in close proximity to said support means,

(e) a punch,

(f) means fixedly mounting said punch to be carried at about themidpoint of said beam and to extend beyond the beam in a direction topress said subject, and

(g) means for operating said punch for a pressing op eration on thesubject in which said beam flexes to guide said punch in alignment withsaid subject.

2. A device according to claim 1 further including,

(h) a second flexible beam, and means fixed to the beam only at the endsof the beam and mounting said second beam on said base parallel to theother beam and spaced from said other beam in a direction away from saidmeans to support the material to be pressed, and,

(i) a spacer connecting said first and second beams at their midregions.

3. A device for pressing material in a die, comprising,

(a) a base, a die, and means mounted on said base to support said die,

(b) a first flexible beam, an upper punch, means fixedly mounting saidupper punch to be carried at about the midpoint of said beam, and meansfixed to said first beam only at its two ends and mounting said beamabove said die support in close proximity to said support with saidupper punch aligned with said die,

(c) a second flexible beam, a lower punch, means fixedly mounting saidlower punch to be carried at about the midpoint of said second beam, andmeans fixed to said second beam only at its two ends and mounting saidbeam below said die support in close proximity to said support with saidlower punch aligned with said die, and

((1) means to operate said upper and lower punches through an operationof pressing material in the cavity of said die in which said beams flexto guide said punches in alignment with said die.

4. A press, comprising,

a base, a die, and means mounted on said base to support said die,

a first pair of flexible beams, a spacer fixedly connecting said beamsat their midpoints, an upper punch fixedly mounted on said spacer, andmeans connected to said beams only at their ends and mounted on andabove said die support for aligning said upper punch above said die,

a second pair of flexible beams, a spacer fixedly connecting said beamsat their midpoints, a lower punch fixedly mounted on said spacer, andmeans connected to said beams only at their ends and mounted on andbelow said die support for aligning said lower punch with said die, and

means for operating said upper and lower punches through a pressingoperation in which said beams flex to guide said punches in alignmentwith said die.

5. A press according to claim 4 in which said operating means comprisescam means for lowering said upper punch through a predetermined path fora pressing operation and raising said upper punch to permit ejecting asubject pressed in said die after a pressing operation and said pressfurther includes auxiliary spring means positioned to engage said lowerpunch near the end of its downward travel in response to said cam meansto apply a substantially uniform force on each subject being pressed.

6. A press for cores, comprising,

a base, a die, means mounted on said base to support said die, a corerod, and means mounted below said die support and spaced from saidsupport in the region of said die and supporting said core rod extendinginto the aperture of said die,

a first pair of flexible beams constructed to flex in one direction andto be rigid in other directions, a spacer fixedly connecting said beamsat their midpoints and spacing apart said beams in their direction offlexing, an upper punch fixedly mounted on said spacer, and means fixedto said beams only at their outer ends and mounted above said diesupport for aligning said upper punch with said die,

a second pair of flexible beams constructed to flex in one direction andto be rigid in other directions, means fixed to one of said beams onlyat its ends and positioning said one beam to extend through the spacebetween said core rod support and said die support in close proximity atits midpoint to said die in a direction toward and away from said die,means fixed to the other of said beams only at its ends for positioningsaid other beam below and generally parallel to said one beam for saidbeam to be fixed in the same direction as said one beam, a spacerfixedly connecting said beams at their midpoints, and a lower punchhaving an axial bore for receiving said core rod fixedly mounted on saidspacer and aligned with said die, and

means for operating said upper and lower punches through a core pressingoperation in which said beams flex to guide said punches in alignmentwith said die.

7. A core press according to claim 6 in which said operating meanscomprises cam means for lowering said upper punch through apredetermined path for a core pressing operation and raising said upperpunch to permit ejecting a core after a pressing operation and saidpress further includes auxiliary spring means positioned to engage saidlower punch near the end of its downward travel in response to said cammeans to apply a substantially uniform force on the cores.

References Cited UNITED STATES PATENTS 1,766,265 6/1930 Smith 18-16.5 X2,122,874 7/1938 Whipple 18-16.5 X 2,127,994 8/1938 Davis et a1 1816.5 X2,150,097 3/1939 Gunderson 1'816 2,411,379 11/1946 Langhammer 18l6.72,481,232 9/1949 Moore 1816 X 2,488,581 11/1949 Cherry et a1 1816 X2,570,989 10/1951 Seelig 18--16.5 2,651,180 9/1953 Haller 18=16 X2,800,684 7/1957 Luthman 18-16.5 3,020,589 2/1962 Maritano 1816.53,132,379 11/1964 C-rane 18-16.5 3,149,375 9/1964 Gehl 1816.5 3,191,2326/1965 Haller 18-16.7 3,328,842 7/1967 Vinson 18--16.5 3,353,215 11/1967Haller 18-16.7 3,382,540 5/1968 Van DeMaden et a1. 1 8-16 X 3,389,4326/1968 Griesheimer et a1. 1816.7

I. HOWARD FLINT, 111., Primary Examiner US. Cl, X.R. 18-16

